convert.con commit Merge branch 'jk/sha1-loose-object-info-fix' (40abbe4)
   1#define NO_THE_INDEX_COMPATIBILITY_MACROS
   2#include "cache.h"
   3#include "config.h"
   4#include "attr.h"
   5#include "run-command.h"
   6#include "quote.h"
   7#include "sigchain.h"
   8#include "pkt-line.h"
   9#include "sub-process.h"
  10
  11/*
  12 * convert.c - convert a file when checking it out and checking it in.
  13 *
  14 * This should use the pathname to decide on whether it wants to do some
  15 * more interesting conversions (automatic gzip/unzip, general format
  16 * conversions etc etc), but by default it just does automatic CRLF<->LF
  17 * translation when the "text" attribute or "auto_crlf" option is set.
  18 */
  19
  20/* Stat bits: When BIN is set, the txt bits are unset */
  21#define CONVERT_STAT_BITS_TXT_LF    0x1
  22#define CONVERT_STAT_BITS_TXT_CRLF  0x2
  23#define CONVERT_STAT_BITS_BIN       0x4
  24
  25enum crlf_action {
  26        CRLF_UNDEFINED,
  27        CRLF_BINARY,
  28        CRLF_TEXT,
  29        CRLF_TEXT_INPUT,
  30        CRLF_TEXT_CRLF,
  31        CRLF_AUTO,
  32        CRLF_AUTO_INPUT,
  33        CRLF_AUTO_CRLF
  34};
  35
  36struct text_stat {
  37        /* NUL, CR, LF and CRLF counts */
  38        unsigned nul, lonecr, lonelf, crlf;
  39
  40        /* These are just approximations! */
  41        unsigned printable, nonprintable;
  42};
  43
  44static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  45{
  46        unsigned long i;
  47
  48        memset(stats, 0, sizeof(*stats));
  49
  50        for (i = 0; i < size; i++) {
  51                unsigned char c = buf[i];
  52                if (c == '\r') {
  53                        if (i+1 < size && buf[i+1] == '\n') {
  54                                stats->crlf++;
  55                                i++;
  56                        } else
  57                                stats->lonecr++;
  58                        continue;
  59                }
  60                if (c == '\n') {
  61                        stats->lonelf++;
  62                        continue;
  63                }
  64                if (c == 127)
  65                        /* DEL */
  66                        stats->nonprintable++;
  67                else if (c < 32) {
  68                        switch (c) {
  69                                /* BS, HT, ESC and FF */
  70                        case '\b': case '\t': case '\033': case '\014':
  71                                stats->printable++;
  72                                break;
  73                        case 0:
  74                                stats->nul++;
  75                                /* fall through */
  76                        default:
  77                                stats->nonprintable++;
  78                        }
  79                }
  80                else
  81                        stats->printable++;
  82        }
  83
  84        /* If file ends with EOF then don't count this EOF as non-printable. */
  85        if (size >= 1 && buf[size-1] == '\032')
  86                stats->nonprintable--;
  87}
  88
  89/*
  90 * The same heuristics as diff.c::mmfile_is_binary()
  91 * We treat files with bare CR as binary
  92 */
  93static int convert_is_binary(unsigned long size, const struct text_stat *stats)
  94{
  95        if (stats->lonecr)
  96                return 1;
  97        if (stats->nul)
  98                return 1;
  99        if ((stats->printable >> 7) < stats->nonprintable)
 100                return 1;
 101        return 0;
 102}
 103
 104static unsigned int gather_convert_stats(const char *data, unsigned long size)
 105{
 106        struct text_stat stats;
 107        int ret = 0;
 108        if (!data || !size)
 109                return 0;
 110        gather_stats(data, size, &stats);
 111        if (convert_is_binary(size, &stats))
 112                ret |= CONVERT_STAT_BITS_BIN;
 113        if (stats.crlf)
 114                ret |= CONVERT_STAT_BITS_TXT_CRLF;
 115        if (stats.lonelf)
 116                ret |=  CONVERT_STAT_BITS_TXT_LF;
 117
 118        return ret;
 119}
 120
 121static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
 122{
 123        unsigned int convert_stats = gather_convert_stats(data, size);
 124
 125        if (convert_stats & CONVERT_STAT_BITS_BIN)
 126                return "-text";
 127        switch (convert_stats) {
 128        case CONVERT_STAT_BITS_TXT_LF:
 129                return "lf";
 130        case CONVERT_STAT_BITS_TXT_CRLF:
 131                return "crlf";
 132        case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
 133                return "mixed";
 134        default:
 135                return "none";
 136        }
 137}
 138
 139const char *get_cached_convert_stats_ascii(const struct index_state *istate,
 140                                           const char *path)
 141{
 142        const char *ret;
 143        unsigned long sz;
 144        void *data = read_blob_data_from_index(istate, path, &sz);
 145        ret = gather_convert_stats_ascii(data, sz);
 146        free(data);
 147        return ret;
 148}
 149
 150const char *get_wt_convert_stats_ascii(const char *path)
 151{
 152        const char *ret = "";
 153        struct strbuf sb = STRBUF_INIT;
 154        if (strbuf_read_file(&sb, path, 0) >= 0)
 155                ret = gather_convert_stats_ascii(sb.buf, sb.len);
 156        strbuf_release(&sb);
 157        return ret;
 158}
 159
 160static int text_eol_is_crlf(void)
 161{
 162        if (auto_crlf == AUTO_CRLF_TRUE)
 163                return 1;
 164        else if (auto_crlf == AUTO_CRLF_INPUT)
 165                return 0;
 166        if (core_eol == EOL_CRLF)
 167                return 1;
 168        if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
 169                return 1;
 170        return 0;
 171}
 172
 173static enum eol output_eol(enum crlf_action crlf_action)
 174{
 175        switch (crlf_action) {
 176        case CRLF_BINARY:
 177                return EOL_UNSET;
 178        case CRLF_TEXT_CRLF:
 179                return EOL_CRLF;
 180        case CRLF_TEXT_INPUT:
 181                return EOL_LF;
 182        case CRLF_UNDEFINED:
 183        case CRLF_AUTO_CRLF:
 184                return EOL_CRLF;
 185        case CRLF_AUTO_INPUT:
 186                return EOL_LF;
 187        case CRLF_TEXT:
 188        case CRLF_AUTO:
 189                /* fall through */
 190                return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
 191        }
 192        warning("Illegal crlf_action %d\n", (int)crlf_action);
 193        return core_eol;
 194}
 195
 196static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
 197                            struct text_stat *old_stats, struct text_stat *new_stats,
 198                            enum safe_crlf checksafe)
 199{
 200        if (old_stats->crlf && !new_stats->crlf ) {
 201                /*
 202                 * CRLFs would not be restored by checkout
 203                 */
 204                if (checksafe == SAFE_CRLF_WARN)
 205                        warning(_("CRLF will be replaced by LF in %s.\n"
 206                                  "The file will have its original line"
 207                                  " endings in your working directory."), path);
 208                else /* i.e. SAFE_CRLF_FAIL */
 209                        die(_("CRLF would be replaced by LF in %s."), path);
 210        } else if (old_stats->lonelf && !new_stats->lonelf ) {
 211                /*
 212                 * CRLFs would be added by checkout
 213                 */
 214                if (checksafe == SAFE_CRLF_WARN)
 215                        warning(_("LF will be replaced by CRLF in %s.\n"
 216                                  "The file will have its original line"
 217                                  " endings in your working directory."), path);
 218                else /* i.e. SAFE_CRLF_FAIL */
 219                        die(_("LF would be replaced by CRLF in %s"), path);
 220        }
 221}
 222
 223static int has_cr_in_index(const struct index_state *istate, const char *path)
 224{
 225        unsigned long sz;
 226        void *data;
 227        int has_cr;
 228
 229        data = read_blob_data_from_index(istate, path, &sz);
 230        if (!data)
 231                return 0;
 232        has_cr = memchr(data, '\r', sz) != NULL;
 233        free(data);
 234        return has_cr;
 235}
 236
 237static int will_convert_lf_to_crlf(size_t len, struct text_stat *stats,
 238                                   enum crlf_action crlf_action)
 239{
 240        if (output_eol(crlf_action) != EOL_CRLF)
 241                return 0;
 242        /* No "naked" LF? Nothing to convert, regardless. */
 243        if (!stats->lonelf)
 244                return 0;
 245
 246        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 247                /* If we have any CR or CRLF line endings, we do not touch it */
 248                /* This is the new safer autocrlf-handling */
 249                if (stats->lonecr || stats->crlf)
 250                        return 0;
 251
 252                if (convert_is_binary(len, stats))
 253                        return 0;
 254        }
 255        return 1;
 256
 257}
 258
 259static int crlf_to_git(const struct index_state *istate,
 260                       const char *path, const char *src, size_t len,
 261                       struct strbuf *buf,
 262                       enum crlf_action crlf_action, enum safe_crlf checksafe)
 263{
 264        struct text_stat stats;
 265        char *dst;
 266        int convert_crlf_into_lf;
 267
 268        if (crlf_action == CRLF_BINARY ||
 269            (src && !len))
 270                return 0;
 271
 272        /*
 273         * If we are doing a dry-run and have no source buffer, there is
 274         * nothing to analyze; we must assume we would convert.
 275         */
 276        if (!buf && !src)
 277                return 1;
 278
 279        gather_stats(src, len, &stats);
 280        /* Optimization: No CRLF? Nothing to convert, regardless. */
 281        convert_crlf_into_lf = !!stats.crlf;
 282
 283        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 284                if (convert_is_binary(len, &stats))
 285                        return 0;
 286                /*
 287                 * If the file in the index has any CR in it, do not
 288                 * convert.  This is the new safer autocrlf handling,
 289                 * unless we want to renormalize in a merge or
 290                 * cherry-pick.
 291                 */
 292                if ((checksafe != SAFE_CRLF_RENORMALIZE) &&
 293                    has_cr_in_index(istate, path))
 294                        convert_crlf_into_lf = 0;
 295        }
 296        if ((checksafe == SAFE_CRLF_WARN ||
 297            (checksafe == SAFE_CRLF_FAIL)) && len) {
 298                struct text_stat new_stats;
 299                memcpy(&new_stats, &stats, sizeof(new_stats));
 300                /* simulate "git add" */
 301                if (convert_crlf_into_lf) {
 302                        new_stats.lonelf += new_stats.crlf;
 303                        new_stats.crlf = 0;
 304                }
 305                /* simulate "git checkout" */
 306                if (will_convert_lf_to_crlf(len, &new_stats, crlf_action)) {
 307                        new_stats.crlf += new_stats.lonelf;
 308                        new_stats.lonelf = 0;
 309                }
 310                check_safe_crlf(path, crlf_action, &stats, &new_stats, checksafe);
 311        }
 312        if (!convert_crlf_into_lf)
 313                return 0;
 314
 315        /*
 316         * At this point all of our source analysis is done, and we are sure we
 317         * would convert. If we are in dry-run mode, we can give an answer.
 318         */
 319        if (!buf)
 320                return 1;
 321
 322        /* only grow if not in place */
 323        if (strbuf_avail(buf) + buf->len < len)
 324                strbuf_grow(buf, len - buf->len);
 325        dst = buf->buf;
 326        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 327                /*
 328                 * If we guessed, we already know we rejected a file with
 329                 * lone CR, and we can strip a CR without looking at what
 330                 * follow it.
 331                 */
 332                do {
 333                        unsigned char c = *src++;
 334                        if (c != '\r')
 335                                *dst++ = c;
 336                } while (--len);
 337        } else {
 338                do {
 339                        unsigned char c = *src++;
 340                        if (! (c == '\r' && (1 < len && *src == '\n')))
 341                                *dst++ = c;
 342                } while (--len);
 343        }
 344        strbuf_setlen(buf, dst - buf->buf);
 345        return 1;
 346}
 347
 348static int crlf_to_worktree(const char *path, const char *src, size_t len,
 349                            struct strbuf *buf, enum crlf_action crlf_action)
 350{
 351        char *to_free = NULL;
 352        struct text_stat stats;
 353
 354        if (!len || output_eol(crlf_action) != EOL_CRLF)
 355                return 0;
 356
 357        gather_stats(src, len, &stats);
 358        if (!will_convert_lf_to_crlf(len, &stats, crlf_action))
 359                return 0;
 360
 361        /* are we "faking" in place editing ? */
 362        if (src == buf->buf)
 363                to_free = strbuf_detach(buf, NULL);
 364
 365        strbuf_grow(buf, len + stats.lonelf);
 366        for (;;) {
 367                const char *nl = memchr(src, '\n', len);
 368                if (!nl)
 369                        break;
 370                if (nl > src && nl[-1] == '\r') {
 371                        strbuf_add(buf, src, nl + 1 - src);
 372                } else {
 373                        strbuf_add(buf, src, nl - src);
 374                        strbuf_addstr(buf, "\r\n");
 375                }
 376                len -= nl + 1 - src;
 377                src  = nl + 1;
 378        }
 379        strbuf_add(buf, src, len);
 380
 381        free(to_free);
 382        return 1;
 383}
 384
 385struct filter_params {
 386        const char *src;
 387        unsigned long size;
 388        int fd;
 389        const char *cmd;
 390        const char *path;
 391};
 392
 393static int filter_buffer_or_fd(int in, int out, void *data)
 394{
 395        /*
 396         * Spawn cmd and feed the buffer contents through its stdin.
 397         */
 398        struct child_process child_process = CHILD_PROCESS_INIT;
 399        struct filter_params *params = (struct filter_params *)data;
 400        int write_err, status;
 401        const char *argv[] = { NULL, NULL };
 402
 403        /* apply % substitution to cmd */
 404        struct strbuf cmd = STRBUF_INIT;
 405        struct strbuf path = STRBUF_INIT;
 406        struct strbuf_expand_dict_entry dict[] = {
 407                { "f", NULL, },
 408                { NULL, NULL, },
 409        };
 410
 411        /* quote the path to preserve spaces, etc. */
 412        sq_quote_buf(&path, params->path);
 413        dict[0].value = path.buf;
 414
 415        /* expand all %f with the quoted path */
 416        strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 417        strbuf_release(&path);
 418
 419        argv[0] = cmd.buf;
 420
 421        child_process.argv = argv;
 422        child_process.use_shell = 1;
 423        child_process.in = -1;
 424        child_process.out = out;
 425
 426        if (start_command(&child_process)) {
 427                strbuf_release(&cmd);
 428                return error("cannot fork to run external filter '%s'", params->cmd);
 429        }
 430
 431        sigchain_push(SIGPIPE, SIG_IGN);
 432
 433        if (params->src) {
 434                write_err = (write_in_full(child_process.in,
 435                                           params->src, params->size) < 0);
 436                if (errno == EPIPE)
 437                        write_err = 0;
 438        } else {
 439                write_err = copy_fd(params->fd, child_process.in);
 440                if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
 441                        write_err = 0;
 442        }
 443
 444        if (close(child_process.in))
 445                write_err = 1;
 446        if (write_err)
 447                error("cannot feed the input to external filter '%s'", params->cmd);
 448
 449        sigchain_pop(SIGPIPE);
 450
 451        status = finish_command(&child_process);
 452        if (status)
 453                error("external filter '%s' failed %d", params->cmd, status);
 454
 455        strbuf_release(&cmd);
 456        return (write_err || status);
 457}
 458
 459static int apply_single_file_filter(const char *path, const char *src, size_t len, int fd,
 460                        struct strbuf *dst, const char *cmd)
 461{
 462        /*
 463         * Create a pipeline to have the command filter the buffer's
 464         * contents.
 465         *
 466         * (child --> cmd) --> us
 467         */
 468        int err = 0;
 469        struct strbuf nbuf = STRBUF_INIT;
 470        struct async async;
 471        struct filter_params params;
 472
 473        memset(&async, 0, sizeof(async));
 474        async.proc = filter_buffer_or_fd;
 475        async.data = &params;
 476        async.out = -1;
 477        params.src = src;
 478        params.size = len;
 479        params.fd = fd;
 480        params.cmd = cmd;
 481        params.path = path;
 482
 483        fflush(NULL);
 484        if (start_async(&async))
 485                return 0;       /* error was already reported */
 486
 487        if (strbuf_read(&nbuf, async.out, len) < 0) {
 488                err = error("read from external filter '%s' failed", cmd);
 489        }
 490        if (close(async.out)) {
 491                err = error("read from external filter '%s' failed", cmd);
 492        }
 493        if (finish_async(&async)) {
 494                err = error("external filter '%s' failed", cmd);
 495        }
 496
 497        if (!err) {
 498                strbuf_swap(dst, &nbuf);
 499        }
 500        strbuf_release(&nbuf);
 501        return !err;
 502}
 503
 504#define CAP_CLEAN    (1u<<0)
 505#define CAP_SMUDGE   (1u<<1)
 506#define CAP_DELAY    (1u<<2)
 507
 508struct cmd2process {
 509        struct subprocess_entry subprocess; /* must be the first member! */
 510        unsigned int supported_capabilities;
 511};
 512
 513static int subprocess_map_initialized;
 514static struct hashmap subprocess_map;
 515
 516static int start_multi_file_filter_fn(struct subprocess_entry *subprocess)
 517{
 518        static int versions[] = {2, 0};
 519        static struct subprocess_capability capabilities[] = {
 520                { "clean",  CAP_CLEAN  },
 521                { "smudge", CAP_SMUDGE },
 522                { "delay",  CAP_DELAY  },
 523                { NULL, 0 }
 524        };
 525        struct cmd2process *entry = (struct cmd2process *)subprocess;
 526        return subprocess_handshake(subprocess, "git-filter", versions, NULL,
 527                                    capabilities,
 528                                    &entry->supported_capabilities);
 529}
 530
 531static void handle_filter_error(const struct strbuf *filter_status,
 532                                struct cmd2process *entry,
 533                                const unsigned int wanted_capability) {
 534        if (!strcmp(filter_status->buf, "error"))
 535                ; /* The filter signaled a problem with the file. */
 536        else if (!strcmp(filter_status->buf, "abort") && wanted_capability) {
 537                /*
 538                 * The filter signaled a permanent problem. Don't try to filter
 539                 * files with the same command for the lifetime of the current
 540                 * Git process.
 541                 */
 542                 entry->supported_capabilities &= ~wanted_capability;
 543        } else {
 544                /*
 545                 * Something went wrong with the protocol filter.
 546                 * Force shutdown and restart if another blob requires filtering.
 547                 */
 548                error("external filter '%s' failed", entry->subprocess.cmd);
 549                subprocess_stop(&subprocess_map, &entry->subprocess);
 550                free(entry);
 551        }
 552}
 553
 554static int apply_multi_file_filter(const char *path, const char *src, size_t len,
 555                                   int fd, struct strbuf *dst, const char *cmd,
 556                                   const unsigned int wanted_capability,
 557                                   struct delayed_checkout *dco)
 558{
 559        int err;
 560        int can_delay = 0;
 561        struct cmd2process *entry;
 562        struct child_process *process;
 563        struct strbuf nbuf = STRBUF_INIT;
 564        struct strbuf filter_status = STRBUF_INIT;
 565        const char *filter_type;
 566
 567        if (!subprocess_map_initialized) {
 568                subprocess_map_initialized = 1;
 569                hashmap_init(&subprocess_map, cmd2process_cmp, NULL, 0);
 570                entry = NULL;
 571        } else {
 572                entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
 573        }
 574
 575        fflush(NULL);
 576
 577        if (!entry) {
 578                entry = xmalloc(sizeof(*entry));
 579                entry->supported_capabilities = 0;
 580
 581                if (subprocess_start(&subprocess_map, &entry->subprocess, cmd, start_multi_file_filter_fn)) {
 582                        free(entry);
 583                        return 0;
 584                }
 585        }
 586        process = &entry->subprocess.process;
 587
 588        if (!(entry->supported_capabilities & wanted_capability))
 589                return 0;
 590
 591        if (wanted_capability & CAP_CLEAN)
 592                filter_type = "clean";
 593        else if (wanted_capability & CAP_SMUDGE)
 594                filter_type = "smudge";
 595        else
 596                die("unexpected filter type");
 597
 598        sigchain_push(SIGPIPE, SIG_IGN);
 599
 600        assert(strlen(filter_type) < LARGE_PACKET_DATA_MAX - strlen("command=\n"));
 601        err = packet_write_fmt_gently(process->in, "command=%s\n", filter_type);
 602        if (err)
 603                goto done;
 604
 605        err = strlen(path) > LARGE_PACKET_DATA_MAX - strlen("pathname=\n");
 606        if (err) {
 607                error("path name too long for external filter");
 608                goto done;
 609        }
 610
 611        err = packet_write_fmt_gently(process->in, "pathname=%s\n", path);
 612        if (err)
 613                goto done;
 614
 615        if ((entry->supported_capabilities & CAP_DELAY) &&
 616            dco && dco->state == CE_CAN_DELAY) {
 617                can_delay = 1;
 618                err = packet_write_fmt_gently(process->in, "can-delay=1\n");
 619                if (err)
 620                        goto done;
 621        }
 622
 623        err = packet_flush_gently(process->in);
 624        if (err)
 625                goto done;
 626
 627        if (fd >= 0)
 628                err = write_packetized_from_fd(fd, process->in);
 629        else
 630                err = write_packetized_from_buf(src, len, process->in);
 631        if (err)
 632                goto done;
 633
 634        err = subprocess_read_status(process->out, &filter_status);
 635        if (err)
 636                goto done;
 637
 638        if (can_delay && !strcmp(filter_status.buf, "delayed")) {
 639                string_list_insert(&dco->filters, cmd);
 640                string_list_insert(&dco->paths, path);
 641        } else {
 642                /* The filter got the blob and wants to send us a response. */
 643                err = strcmp(filter_status.buf, "success");
 644                if (err)
 645                        goto done;
 646
 647                err = read_packetized_to_strbuf(process->out, &nbuf) < 0;
 648                if (err)
 649                        goto done;
 650
 651                err = subprocess_read_status(process->out, &filter_status);
 652                if (err)
 653                        goto done;
 654
 655                err = strcmp(filter_status.buf, "success");
 656        }
 657
 658done:
 659        sigchain_pop(SIGPIPE);
 660
 661        if (err)
 662                handle_filter_error(&filter_status, entry, wanted_capability);
 663        else
 664                strbuf_swap(dst, &nbuf);
 665        strbuf_release(&nbuf);
 666        return !err;
 667}
 668
 669
 670int async_query_available_blobs(const char *cmd, struct string_list *available_paths)
 671{
 672        int err;
 673        char *line;
 674        struct cmd2process *entry;
 675        struct child_process *process;
 676        struct strbuf filter_status = STRBUF_INIT;
 677
 678        assert(subprocess_map_initialized);
 679        entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
 680        if (!entry) {
 681                error("external filter '%s' is not available anymore although "
 682                      "not all paths have been filtered", cmd);
 683                return 0;
 684        }
 685        process = &entry->subprocess.process;
 686        sigchain_push(SIGPIPE, SIG_IGN);
 687
 688        err = packet_write_fmt_gently(
 689                process->in, "command=list_available_blobs\n");
 690        if (err)
 691                goto done;
 692
 693        err = packet_flush_gently(process->in);
 694        if (err)
 695                goto done;
 696
 697        while ((line = packet_read_line(process->out, NULL))) {
 698                const char *path;
 699                if (skip_prefix(line, "pathname=", &path))
 700                        string_list_insert(available_paths, xstrdup(path));
 701                else
 702                        ; /* ignore unknown keys */
 703        }
 704
 705        err = subprocess_read_status(process->out, &filter_status);
 706        if (err)
 707                goto done;
 708
 709        err = strcmp(filter_status.buf, "success");
 710
 711done:
 712        sigchain_pop(SIGPIPE);
 713
 714        if (err)
 715                handle_filter_error(&filter_status, entry, 0);
 716        return !err;
 717}
 718
 719static struct convert_driver {
 720        const char *name;
 721        struct convert_driver *next;
 722        const char *smudge;
 723        const char *clean;
 724        const char *process;
 725        int required;
 726} *user_convert, **user_convert_tail;
 727
 728static int apply_filter(const char *path, const char *src, size_t len,
 729                        int fd, struct strbuf *dst, struct convert_driver *drv,
 730                        const unsigned int wanted_capability,
 731                        struct delayed_checkout *dco)
 732{
 733        const char *cmd = NULL;
 734
 735        if (!drv)
 736                return 0;
 737
 738        if (!dst)
 739                return 1;
 740
 741        if ((wanted_capability & CAP_CLEAN) && !drv->process && drv->clean)
 742                cmd = drv->clean;
 743        else if ((wanted_capability & CAP_SMUDGE) && !drv->process && drv->smudge)
 744                cmd = drv->smudge;
 745
 746        if (cmd && *cmd)
 747                return apply_single_file_filter(path, src, len, fd, dst, cmd);
 748        else if (drv->process && *drv->process)
 749                return apply_multi_file_filter(path, src, len, fd, dst,
 750                        drv->process, wanted_capability, dco);
 751
 752        return 0;
 753}
 754
 755static int read_convert_config(const char *var, const char *value, void *cb)
 756{
 757        const char *key, *name;
 758        int namelen;
 759        struct convert_driver *drv;
 760
 761        /*
 762         * External conversion drivers are configured using
 763         * "filter.<name>.variable".
 764         */
 765        if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 766                return 0;
 767        for (drv = user_convert; drv; drv = drv->next)
 768                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 769                        break;
 770        if (!drv) {
 771                drv = xcalloc(1, sizeof(struct convert_driver));
 772                drv->name = xmemdupz(name, namelen);
 773                *user_convert_tail = drv;
 774                user_convert_tail = &(drv->next);
 775        }
 776
 777        /*
 778         * filter.<name>.smudge and filter.<name>.clean specifies
 779         * the command line:
 780         *
 781         *      command-line
 782         *
 783         * The command-line will not be interpolated in any way.
 784         */
 785
 786        if (!strcmp("smudge", key))
 787                return git_config_string(&drv->smudge, var, value);
 788
 789        if (!strcmp("clean", key))
 790                return git_config_string(&drv->clean, var, value);
 791
 792        if (!strcmp("process", key))
 793                return git_config_string(&drv->process, var, value);
 794
 795        if (!strcmp("required", key)) {
 796                drv->required = git_config_bool(var, value);
 797                return 0;
 798        }
 799
 800        return 0;
 801}
 802
 803static int count_ident(const char *cp, unsigned long size)
 804{
 805        /*
 806         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 807         */
 808        int cnt = 0;
 809        char ch;
 810
 811        while (size) {
 812                ch = *cp++;
 813                size--;
 814                if (ch != '$')
 815                        continue;
 816                if (size < 3)
 817                        break;
 818                if (memcmp("Id", cp, 2))
 819                        continue;
 820                ch = cp[2];
 821                cp += 3;
 822                size -= 3;
 823                if (ch == '$')
 824                        cnt++; /* $Id$ */
 825                if (ch != ':')
 826                        continue;
 827
 828                /*
 829                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 830                 */
 831                while (size) {
 832                        ch = *cp++;
 833                        size--;
 834                        if (ch == '$') {
 835                                cnt++;
 836                                break;
 837                        }
 838                        if (ch == '\n')
 839                                break;
 840                }
 841        }
 842        return cnt;
 843}
 844
 845static int ident_to_git(const char *path, const char *src, size_t len,
 846                        struct strbuf *buf, int ident)
 847{
 848        char *dst, *dollar;
 849
 850        if (!ident || (src && !count_ident(src, len)))
 851                return 0;
 852
 853        if (!buf)
 854                return 1;
 855
 856        /* only grow if not in place */
 857        if (strbuf_avail(buf) + buf->len < len)
 858                strbuf_grow(buf, len - buf->len);
 859        dst = buf->buf;
 860        for (;;) {
 861                dollar = memchr(src, '$', len);
 862                if (!dollar)
 863                        break;
 864                memmove(dst, src, dollar + 1 - src);
 865                dst += dollar + 1 - src;
 866                len -= dollar + 1 - src;
 867                src  = dollar + 1;
 868
 869                if (len > 3 && !memcmp(src, "Id:", 3)) {
 870                        dollar = memchr(src + 3, '$', len - 3);
 871                        if (!dollar)
 872                                break;
 873                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 874                                /* Line break before the next dollar. */
 875                                continue;
 876                        }
 877
 878                        memcpy(dst, "Id$", 3);
 879                        dst += 3;
 880                        len -= dollar + 1 - src;
 881                        src  = dollar + 1;
 882                }
 883        }
 884        memmove(dst, src, len);
 885        strbuf_setlen(buf, dst + len - buf->buf);
 886        return 1;
 887}
 888
 889static int ident_to_worktree(const char *path, const char *src, size_t len,
 890                             struct strbuf *buf, int ident)
 891{
 892        unsigned char sha1[20];
 893        char *to_free = NULL, *dollar, *spc;
 894        int cnt;
 895
 896        if (!ident)
 897                return 0;
 898
 899        cnt = count_ident(src, len);
 900        if (!cnt)
 901                return 0;
 902
 903        /* are we "faking" in place editing ? */
 904        if (src == buf->buf)
 905                to_free = strbuf_detach(buf, NULL);
 906        hash_sha1_file(src, len, "blob", sha1);
 907
 908        strbuf_grow(buf, len + cnt * 43);
 909        for (;;) {
 910                /* step 1: run to the next '$' */
 911                dollar = memchr(src, '$', len);
 912                if (!dollar)
 913                        break;
 914                strbuf_add(buf, src, dollar + 1 - src);
 915                len -= dollar + 1 - src;
 916                src  = dollar + 1;
 917
 918                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 919                if (len < 3 || memcmp("Id", src, 2))
 920                        continue;
 921
 922                /* step 3: skip over Id$ or Id:xxxxx$ */
 923                if (src[2] == '$') {
 924                        src += 3;
 925                        len -= 3;
 926                } else if (src[2] == ':') {
 927                        /*
 928                         * It's possible that an expanded Id has crept its way into the
 929                         * repository, we cope with that by stripping the expansion out.
 930                         * This is probably not a good idea, since it will cause changes
 931                         * on checkout, which won't go away by stash, but let's keep it
 932                         * for git-style ids.
 933                         */
 934                        dollar = memchr(src + 3, '$', len - 3);
 935                        if (!dollar) {
 936                                /* incomplete keyword, no more '$', so just quit the loop */
 937                                break;
 938                        }
 939
 940                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 941                                /* Line break before the next dollar. */
 942                                continue;
 943                        }
 944
 945                        spc = memchr(src + 4, ' ', dollar - src - 4);
 946                        if (spc && spc < dollar-1) {
 947                                /* There are spaces in unexpected places.
 948                                 * This is probably an id from some other
 949                                 * versioning system. Keep it for now.
 950                                 */
 951                                continue;
 952                        }
 953
 954                        len -= dollar + 1 - src;
 955                        src  = dollar + 1;
 956                } else {
 957                        /* it wasn't a "Id$" or "Id:xxxx$" */
 958                        continue;
 959                }
 960
 961                /* step 4: substitute */
 962                strbuf_addstr(buf, "Id: ");
 963                strbuf_add(buf, sha1_to_hex(sha1), 40);
 964                strbuf_addstr(buf, " $");
 965        }
 966        strbuf_add(buf, src, len);
 967
 968        free(to_free);
 969        return 1;
 970}
 971
 972static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
 973{
 974        const char *value = check->value;
 975
 976        if (ATTR_TRUE(value))
 977                return CRLF_TEXT;
 978        else if (ATTR_FALSE(value))
 979                return CRLF_BINARY;
 980        else if (ATTR_UNSET(value))
 981                ;
 982        else if (!strcmp(value, "input"))
 983                return CRLF_TEXT_INPUT;
 984        else if (!strcmp(value, "auto"))
 985                return CRLF_AUTO;
 986        return CRLF_UNDEFINED;
 987}
 988
 989static enum eol git_path_check_eol(struct attr_check_item *check)
 990{
 991        const char *value = check->value;
 992
 993        if (ATTR_UNSET(value))
 994                ;
 995        else if (!strcmp(value, "lf"))
 996                return EOL_LF;
 997        else if (!strcmp(value, "crlf"))
 998                return EOL_CRLF;
 999        return EOL_UNSET;
1000}
1001
1002static struct convert_driver *git_path_check_convert(struct attr_check_item *check)
1003{
1004        const char *value = check->value;
1005        struct convert_driver *drv;
1006
1007        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1008                return NULL;
1009        for (drv = user_convert; drv; drv = drv->next)
1010                if (!strcmp(value, drv->name))
1011                        return drv;
1012        return NULL;
1013}
1014
1015static int git_path_check_ident(struct attr_check_item *check)
1016{
1017        const char *value = check->value;
1018
1019        return !!ATTR_TRUE(value);
1020}
1021
1022struct conv_attrs {
1023        struct convert_driver *drv;
1024        enum crlf_action attr_action; /* What attr says */
1025        enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
1026        int ident;
1027};
1028
1029static void convert_attrs(struct conv_attrs *ca, const char *path)
1030{
1031        static struct attr_check *check;
1032
1033        if (!check) {
1034                check = attr_check_initl("crlf", "ident", "filter",
1035                                         "eol", "text", NULL);
1036                user_convert_tail = &user_convert;
1037                git_config(read_convert_config, NULL);
1038        }
1039
1040        if (!git_check_attr(path, check)) {
1041                struct attr_check_item *ccheck = check->items;
1042                ca->crlf_action = git_path_check_crlf(ccheck + 4);
1043                if (ca->crlf_action == CRLF_UNDEFINED)
1044                        ca->crlf_action = git_path_check_crlf(ccheck + 0);
1045                ca->ident = git_path_check_ident(ccheck + 1);
1046                ca->drv = git_path_check_convert(ccheck + 2);
1047                if (ca->crlf_action != CRLF_BINARY) {
1048                        enum eol eol_attr = git_path_check_eol(ccheck + 3);
1049                        if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
1050                                ca->crlf_action = CRLF_AUTO_INPUT;
1051                        else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
1052                                ca->crlf_action = CRLF_AUTO_CRLF;
1053                        else if (eol_attr == EOL_LF)
1054                                ca->crlf_action = CRLF_TEXT_INPUT;
1055                        else if (eol_attr == EOL_CRLF)
1056                                ca->crlf_action = CRLF_TEXT_CRLF;
1057                }
1058        } else {
1059                ca->drv = NULL;
1060                ca->crlf_action = CRLF_UNDEFINED;
1061                ca->ident = 0;
1062        }
1063
1064        /* Save attr and make a decision for action */
1065        ca->attr_action = ca->crlf_action;
1066        if (ca->crlf_action == CRLF_TEXT)
1067                ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
1068        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
1069                ca->crlf_action = CRLF_BINARY;
1070        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
1071                ca->crlf_action = CRLF_AUTO_CRLF;
1072        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
1073                ca->crlf_action = CRLF_AUTO_INPUT;
1074}
1075
1076int would_convert_to_git_filter_fd(const char *path)
1077{
1078        struct conv_attrs ca;
1079
1080        convert_attrs(&ca, path);
1081        if (!ca.drv)
1082                return 0;
1083
1084        /*
1085         * Apply a filter to an fd only if the filter is required to succeed.
1086         * We must die if the filter fails, because the original data before
1087         * filtering is not available.
1088         */
1089        if (!ca.drv->required)
1090                return 0;
1091
1092        return apply_filter(path, NULL, 0, -1, NULL, ca.drv, CAP_CLEAN, NULL);
1093}
1094
1095const char *get_convert_attr_ascii(const char *path)
1096{
1097        struct conv_attrs ca;
1098
1099        convert_attrs(&ca, path);
1100        switch (ca.attr_action) {
1101        case CRLF_UNDEFINED:
1102                return "";
1103        case CRLF_BINARY:
1104                return "-text";
1105        case CRLF_TEXT:
1106                return "text";
1107        case CRLF_TEXT_INPUT:
1108                return "text eol=lf";
1109        case CRLF_TEXT_CRLF:
1110                return "text eol=crlf";
1111        case CRLF_AUTO:
1112                return "text=auto";
1113        case CRLF_AUTO_CRLF:
1114                return "text=auto eol=crlf";
1115        case CRLF_AUTO_INPUT:
1116                return "text=auto eol=lf";
1117        }
1118        return "";
1119}
1120
1121int convert_to_git(const struct index_state *istate,
1122                   const char *path, const char *src, size_t len,
1123                   struct strbuf *dst, enum safe_crlf checksafe)
1124{
1125        int ret = 0;
1126        struct conv_attrs ca;
1127
1128        convert_attrs(&ca, path);
1129
1130        ret |= apply_filter(path, src, len, -1, dst, ca.drv, CAP_CLEAN, NULL);
1131        if (!ret && ca.drv && ca.drv->required)
1132                die("%s: clean filter '%s' failed", path, ca.drv->name);
1133
1134        if (ret && dst) {
1135                src = dst->buf;
1136                len = dst->len;
1137        }
1138        if (checksafe != SAFE_CRLF_KEEP_CRLF) {
1139                ret |= crlf_to_git(istate, path, src, len, dst, ca.crlf_action, checksafe);
1140                if (ret && dst) {
1141                        src = dst->buf;
1142                        len = dst->len;
1143                }
1144        }
1145        return ret | ident_to_git(path, src, len, dst, ca.ident);
1146}
1147
1148void convert_to_git_filter_fd(const struct index_state *istate,
1149                              const char *path, int fd, struct strbuf *dst,
1150                              enum safe_crlf checksafe)
1151{
1152        struct conv_attrs ca;
1153        convert_attrs(&ca, path);
1154
1155        assert(ca.drv);
1156        assert(ca.drv->clean || ca.drv->process);
1157
1158        if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN, NULL))
1159                die("%s: clean filter '%s' failed", path, ca.drv->name);
1160
1161        crlf_to_git(istate, path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
1162        ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
1163}
1164
1165static int convert_to_working_tree_internal(const char *path, const char *src,
1166                                            size_t len, struct strbuf *dst,
1167                                            int normalizing, struct delayed_checkout *dco)
1168{
1169        int ret = 0, ret_filter = 0;
1170        struct conv_attrs ca;
1171
1172        convert_attrs(&ca, path);
1173
1174        ret |= ident_to_worktree(path, src, len, dst, ca.ident);
1175        if (ret) {
1176                src = dst->buf;
1177                len = dst->len;
1178        }
1179        /*
1180         * CRLF conversion can be skipped if normalizing, unless there
1181         * is a smudge or process filter (even if the process filter doesn't
1182         * support smudge).  The filters might expect CRLFs.
1183         */
1184        if ((ca.drv && (ca.drv->smudge || ca.drv->process)) || !normalizing) {
1185                ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
1186                if (ret) {
1187                        src = dst->buf;
1188                        len = dst->len;
1189                }
1190        }
1191
1192        ret_filter = apply_filter(
1193                path, src, len, -1, dst, ca.drv, CAP_SMUDGE, dco);
1194        if (!ret_filter && ca.drv && ca.drv->required)
1195                die("%s: smudge filter %s failed", path, ca.drv->name);
1196
1197        return ret | ret_filter;
1198}
1199
1200int async_convert_to_working_tree(const char *path, const char *src,
1201                                  size_t len, struct strbuf *dst,
1202                                  void *dco)
1203{
1204        return convert_to_working_tree_internal(path, src, len, dst, 0, dco);
1205}
1206
1207int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
1208{
1209        return convert_to_working_tree_internal(path, src, len, dst, 0, NULL);
1210}
1211
1212int renormalize_buffer(const struct index_state *istate, const char *path,
1213                       const char *src, size_t len, struct strbuf *dst)
1214{
1215        int ret = convert_to_working_tree_internal(path, src, len, dst, 1, NULL);
1216        if (ret) {
1217                src = dst->buf;
1218                len = dst->len;
1219        }
1220        return ret | convert_to_git(istate, path, src, len, dst, SAFE_CRLF_RENORMALIZE);
1221}
1222
1223/*****************************************************************
1224 *
1225 * Streaming conversion support
1226 *
1227 *****************************************************************/
1228
1229typedef int (*filter_fn)(struct stream_filter *,
1230                         const char *input, size_t *isize_p,
1231                         char *output, size_t *osize_p);
1232typedef void (*free_fn)(struct stream_filter *);
1233
1234struct stream_filter_vtbl {
1235        filter_fn filter;
1236        free_fn free;
1237};
1238
1239struct stream_filter {
1240        struct stream_filter_vtbl *vtbl;
1241};
1242
1243static int null_filter_fn(struct stream_filter *filter,
1244                          const char *input, size_t *isize_p,
1245                          char *output, size_t *osize_p)
1246{
1247        size_t count;
1248
1249        if (!input)
1250                return 0; /* we do not keep any states */
1251        count = *isize_p;
1252        if (*osize_p < count)
1253                count = *osize_p;
1254        if (count) {
1255                memmove(output, input, count);
1256                *isize_p -= count;
1257                *osize_p -= count;
1258        }
1259        return 0;
1260}
1261
1262static void null_free_fn(struct stream_filter *filter)
1263{
1264        ; /* nothing -- null instances are shared */
1265}
1266
1267static struct stream_filter_vtbl null_vtbl = {
1268        null_filter_fn,
1269        null_free_fn,
1270};
1271
1272static struct stream_filter null_filter_singleton = {
1273        &null_vtbl,
1274};
1275
1276int is_null_stream_filter(struct stream_filter *filter)
1277{
1278        return filter == &null_filter_singleton;
1279}
1280
1281
1282/*
1283 * LF-to-CRLF filter
1284 */
1285
1286struct lf_to_crlf_filter {
1287        struct stream_filter filter;
1288        unsigned has_held:1;
1289        char held;
1290};
1291
1292static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1293                                const char *input, size_t *isize_p,
1294                                char *output, size_t *osize_p)
1295{
1296        size_t count, o = 0;
1297        struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1298
1299        /*
1300         * We may be holding onto the CR to see if it is followed by a
1301         * LF, in which case we would need to go to the main loop.
1302         * Otherwise, just emit it to the output stream.
1303         */
1304        if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1305                output[o++] = lf_to_crlf->held;
1306                lf_to_crlf->has_held = 0;
1307        }
1308
1309        /* We are told to drain */
1310        if (!input) {
1311                *osize_p -= o;
1312                return 0;
1313        }
1314
1315        count = *isize_p;
1316        if (count || lf_to_crlf->has_held) {
1317                size_t i;
1318                int was_cr = 0;
1319
1320                if (lf_to_crlf->has_held) {
1321                        was_cr = 1;
1322                        lf_to_crlf->has_held = 0;
1323                }
1324
1325                for (i = 0; o < *osize_p && i < count; i++) {
1326                        char ch = input[i];
1327
1328                        if (ch == '\n') {
1329                                output[o++] = '\r';
1330                        } else if (was_cr) {
1331                                /*
1332                                 * Previous round saw CR and it is not followed
1333                                 * by a LF; emit the CR before processing the
1334                                 * current character.
1335                                 */
1336                                output[o++] = '\r';
1337                        }
1338
1339                        /*
1340                         * We may have consumed the last output slot,
1341                         * in which case we need to break out of this
1342                         * loop; hold the current character before
1343                         * returning.
1344                         */
1345                        if (*osize_p <= o) {
1346                                lf_to_crlf->has_held = 1;
1347                                lf_to_crlf->held = ch;
1348                                continue; /* break but increment i */
1349                        }
1350
1351                        if (ch == '\r') {
1352                                was_cr = 1;
1353                                continue;
1354                        }
1355
1356                        was_cr = 0;
1357                        output[o++] = ch;
1358                }
1359
1360                *osize_p -= o;
1361                *isize_p -= i;
1362
1363                if (!lf_to_crlf->has_held && was_cr) {
1364                        lf_to_crlf->has_held = 1;
1365                        lf_to_crlf->held = '\r';
1366                }
1367        }
1368        return 0;
1369}
1370
1371static void lf_to_crlf_free_fn(struct stream_filter *filter)
1372{
1373        free(filter);
1374}
1375
1376static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1377        lf_to_crlf_filter_fn,
1378        lf_to_crlf_free_fn,
1379};
1380
1381static struct stream_filter *lf_to_crlf_filter(void)
1382{
1383        struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1384
1385        lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1386        return (struct stream_filter *)lf_to_crlf;
1387}
1388
1389/*
1390 * Cascade filter
1391 */
1392#define FILTER_BUFFER 1024
1393struct cascade_filter {
1394        struct stream_filter filter;
1395        struct stream_filter *one;
1396        struct stream_filter *two;
1397        char buf[FILTER_BUFFER];
1398        int end, ptr;
1399};
1400
1401static int cascade_filter_fn(struct stream_filter *filter,
1402                             const char *input, size_t *isize_p,
1403                             char *output, size_t *osize_p)
1404{
1405        struct cascade_filter *cas = (struct cascade_filter *) filter;
1406        size_t filled = 0;
1407        size_t sz = *osize_p;
1408        size_t to_feed, remaining;
1409
1410        /*
1411         * input -- (one) --> buf -- (two) --> output
1412         */
1413        while (filled < sz) {
1414                remaining = sz - filled;
1415
1416                /* do we already have something to feed two with? */
1417                if (cas->ptr < cas->end) {
1418                        to_feed = cas->end - cas->ptr;
1419                        if (stream_filter(cas->two,
1420                                          cas->buf + cas->ptr, &to_feed,
1421                                          output + filled, &remaining))
1422                                return -1;
1423                        cas->ptr += (cas->end - cas->ptr) - to_feed;
1424                        filled = sz - remaining;
1425                        continue;
1426                }
1427
1428                /* feed one from upstream and have it emit into our buffer */
1429                to_feed = input ? *isize_p : 0;
1430                if (input && !to_feed)
1431                        break;
1432                remaining = sizeof(cas->buf);
1433                if (stream_filter(cas->one,
1434                                  input, &to_feed,
1435                                  cas->buf, &remaining))
1436                        return -1;
1437                cas->end = sizeof(cas->buf) - remaining;
1438                cas->ptr = 0;
1439                if (input) {
1440                        size_t fed = *isize_p - to_feed;
1441                        *isize_p -= fed;
1442                        input += fed;
1443                }
1444
1445                /* do we know that we drained one completely? */
1446                if (input || cas->end)
1447                        continue;
1448
1449                /* tell two to drain; we have nothing more to give it */
1450                to_feed = 0;
1451                remaining = sz - filled;
1452                if (stream_filter(cas->two,
1453                                  NULL, &to_feed,
1454                                  output + filled, &remaining))
1455                        return -1;
1456                if (remaining == (sz - filled))
1457                        break; /* completely drained two */
1458                filled = sz - remaining;
1459        }
1460        *osize_p -= filled;
1461        return 0;
1462}
1463
1464static void cascade_free_fn(struct stream_filter *filter)
1465{
1466        struct cascade_filter *cas = (struct cascade_filter *)filter;
1467        free_stream_filter(cas->one);
1468        free_stream_filter(cas->two);
1469        free(filter);
1470}
1471
1472static struct stream_filter_vtbl cascade_vtbl = {
1473        cascade_filter_fn,
1474        cascade_free_fn,
1475};
1476
1477static struct stream_filter *cascade_filter(struct stream_filter *one,
1478                                            struct stream_filter *two)
1479{
1480        struct cascade_filter *cascade;
1481
1482        if (!one || is_null_stream_filter(one))
1483                return two;
1484        if (!two || is_null_stream_filter(two))
1485                return one;
1486
1487        cascade = xmalloc(sizeof(*cascade));
1488        cascade->one = one;
1489        cascade->two = two;
1490        cascade->end = cascade->ptr = 0;
1491        cascade->filter.vtbl = &cascade_vtbl;
1492        return (struct stream_filter *)cascade;
1493}
1494
1495/*
1496 * ident filter
1497 */
1498#define IDENT_DRAINING (-1)
1499#define IDENT_SKIPPING (-2)
1500struct ident_filter {
1501        struct stream_filter filter;
1502        struct strbuf left;
1503        int state;
1504        char ident[45]; /* ": x40 $" */
1505};
1506
1507static int is_foreign_ident(const char *str)
1508{
1509        int i;
1510
1511        if (!skip_prefix(str, "$Id: ", &str))
1512                return 0;
1513        for (i = 0; str[i]; i++) {
1514                if (isspace(str[i]) && str[i+1] != '$')
1515                        return 1;
1516        }
1517        return 0;
1518}
1519
1520static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1521{
1522        size_t to_drain = ident->left.len;
1523
1524        if (*osize_p < to_drain)
1525                to_drain = *osize_p;
1526        if (to_drain) {
1527                memcpy(*output_p, ident->left.buf, to_drain);
1528                strbuf_remove(&ident->left, 0, to_drain);
1529                *output_p += to_drain;
1530                *osize_p -= to_drain;
1531        }
1532        if (!ident->left.len)
1533                ident->state = 0;
1534}
1535
1536static int ident_filter_fn(struct stream_filter *filter,
1537                           const char *input, size_t *isize_p,
1538                           char *output, size_t *osize_p)
1539{
1540        struct ident_filter *ident = (struct ident_filter *)filter;
1541        static const char head[] = "$Id";
1542
1543        if (!input) {
1544                /* drain upon eof */
1545                switch (ident->state) {
1546                default:
1547                        strbuf_add(&ident->left, head, ident->state);
1548                        /* fallthrough */
1549                case IDENT_SKIPPING:
1550                        /* fallthrough */
1551                case IDENT_DRAINING:
1552                        ident_drain(ident, &output, osize_p);
1553                }
1554                return 0;
1555        }
1556
1557        while (*isize_p || (ident->state == IDENT_DRAINING)) {
1558                int ch;
1559
1560                if (ident->state == IDENT_DRAINING) {
1561                        ident_drain(ident, &output, osize_p);
1562                        if (!*osize_p)
1563                                break;
1564                        continue;
1565                }
1566
1567                ch = *(input++);
1568                (*isize_p)--;
1569
1570                if (ident->state == IDENT_SKIPPING) {
1571                        /*
1572                         * Skipping until '$' or LF, but keeping them
1573                         * in case it is a foreign ident.
1574                         */
1575                        strbuf_addch(&ident->left, ch);
1576                        if (ch != '\n' && ch != '$')
1577                                continue;
1578                        if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1579                                strbuf_setlen(&ident->left, sizeof(head) - 1);
1580                                strbuf_addstr(&ident->left, ident->ident);
1581                        }
1582                        ident->state = IDENT_DRAINING;
1583                        continue;
1584                }
1585
1586                if (ident->state < sizeof(head) &&
1587                    head[ident->state] == ch) {
1588                        ident->state++;
1589                        continue;
1590                }
1591
1592                if (ident->state)
1593                        strbuf_add(&ident->left, head, ident->state);
1594                if (ident->state == sizeof(head) - 1) {
1595                        if (ch != ':' && ch != '$') {
1596                                strbuf_addch(&ident->left, ch);
1597                                ident->state = 0;
1598                                continue;
1599                        }
1600
1601                        if (ch == ':') {
1602                                strbuf_addch(&ident->left, ch);
1603                                ident->state = IDENT_SKIPPING;
1604                        } else {
1605                                strbuf_addstr(&ident->left, ident->ident);
1606                                ident->state = IDENT_DRAINING;
1607                        }
1608                        continue;
1609                }
1610
1611                strbuf_addch(&ident->left, ch);
1612                ident->state = IDENT_DRAINING;
1613        }
1614        return 0;
1615}
1616
1617static void ident_free_fn(struct stream_filter *filter)
1618{
1619        struct ident_filter *ident = (struct ident_filter *)filter;
1620        strbuf_release(&ident->left);
1621        free(filter);
1622}
1623
1624static struct stream_filter_vtbl ident_vtbl = {
1625        ident_filter_fn,
1626        ident_free_fn,
1627};
1628
1629static struct stream_filter *ident_filter(const unsigned char *sha1)
1630{
1631        struct ident_filter *ident = xmalloc(sizeof(*ident));
1632
1633        xsnprintf(ident->ident, sizeof(ident->ident),
1634                  ": %s $", sha1_to_hex(sha1));
1635        strbuf_init(&ident->left, 0);
1636        ident->filter.vtbl = &ident_vtbl;
1637        ident->state = 0;
1638        return (struct stream_filter *)ident;
1639}
1640
1641/*
1642 * Return an appropriately constructed filter for the path, or NULL if
1643 * the contents cannot be filtered without reading the whole thing
1644 * in-core.
1645 *
1646 * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1647 * large binary blob you would want us not to slurp into the memory!
1648 */
1649struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1650{
1651        struct conv_attrs ca;
1652        struct stream_filter *filter = NULL;
1653
1654        convert_attrs(&ca, path);
1655        if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
1656                return NULL;
1657
1658        if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1659                return NULL;
1660
1661        if (ca.ident)
1662                filter = ident_filter(sha1);
1663
1664        if (output_eol(ca.crlf_action) == EOL_CRLF)
1665                filter = cascade_filter(filter, lf_to_crlf_filter());
1666        else
1667                filter = cascade_filter(filter, &null_filter_singleton);
1668
1669        return filter;
1670}
1671
1672void free_stream_filter(struct stream_filter *filter)
1673{
1674        filter->vtbl->free(filter);
1675}
1676
1677int stream_filter(struct stream_filter *filter,
1678                  const char *input, size_t *isize_p,
1679                  char *output, size_t *osize_p)
1680{
1681        return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1682}